Method of manufacturing and use of combustible insert sleeves in the body of solid fuel heaters



Feb. 17, 1970 I c, M. b ERmG ET AL 3,495,924

METHOD OF MANUFACTURING AND USE OF COMBUSTIBLE INSERT SLEEVES IN THE BODY OF SOLID FUEL HEATERS Filed D80. 27, 1967 T'lEll. fiw/o/Pmr) United States Patent Office 3,495,924 Patented Feb. 17, 1970 METHOD OF MANUFACTURING AND USE OF COMBUSTIBLE INSERT SLEEVES IN THE BODY OF SULID FUEL HEATERS Clarence M. Doering, Nederland, and Leonard S. Seni, Port Arthur, Tex., assignors to Texaco lnc., New York, N.Y., a corporation of Delaware Filed Dec. 27, 1967, Ser. No. 693,878

Int. Cl. A0111 9/38, 21/04; A61k 27/60; A611 13/00 U.S. Cl. 431-291 8 Claims ABSTRACT OF THE DISCLOSURE A solid fuel heater comprising a container substantially filled with a solid fuel, having a combustible insert sleeve embedded therewithin, with the top edge of the insert sleeve extending above the surface of the solid fuel, the improvement being that the insert sleeve has supporting legs for predetermined positioning within the container, although the insert sleeve can be used without legs, also.

Background of the invention The present invention is directed to a solid fuel heater with non-extinguishing flame characteristics which is adapted particularly for use as an orchard heater. Included is a combustible insert sleeve which controls the setting of the fuel during cooling, and also serves as a retainer for molten fuel after ignition of the heater. Also included in the invention is a method of producing the insert sleeve.

Description of the prior art In the coassigned patent issued to E. C. Knowles and F. C. McCoy on Aug. 29, 1967, Patent No. 3,338,691, for a Heating Composition, the disclosure of which is incorporated herein by this reference, there is disclosed and claimed, novel heating compositions and methods of making the same, and the methods of using such compositions.

Solid fuel heaters, such as disclosed in this patent, are desirable for use in orchards to protect citrus trees from freezing. However, these heaters, due to their size, their use of solid fuel, and the heat they give off with low flame height, may be used in many other ways, such as camp stoves, personal heaters, emergency signals and the like.

Previously, citrus orchard heaters were in the shape of a rectangular box or upright cylinder and set in an open ended container. Embedded in the heaters were inserts which acted as flame holders during burning to sustain the burning during high winds. Further, hydrocarbon materials were impregnated in the fuel and inserts to aid in supporting combustion.

During fabrication of the heaters, molten fuel is poured into a container wherein it cools and contracts. A wicking means, e.g. oiled perlite, can be added either before or after the pouring. Due to the thermal gradient existing throughout the fuel during cooling, a separation results between the container wall and the cooled contracted solid fuel of the heater. Another void or vug may be formed in the upper central portion of the solid fuel below the wicking means.

When the solid fuel heater is ignited in the field, the fuel closest to the flame melts and floats on top of the still solid fuel. It is desirable that this molten fuel remain on top of the heater in contact with the wicking means to feed the flame. Instead, the melted fuel would drain into the side wall separation or the central vugs and voids which form during cooling, starving the flame. Thus, the heaters would have to be reignited continuously by an operator if the orchard was to be protected.

With one heater for each tree in an orchard, reignition of the heaters can prove to be a continuous and inconvenient task.

Summary of the invention An overall object of the present invention is to provide a solid fuel heater with an insert sleeve therein which acts as a reservoir for molten fuel.

A further object of the present invention is to provide a solid fuel heater capable of burning at a substantially consistent rate, due to the absence of voids or vugs therein. 7

Accordingly, in an embodiment of the present invention there is included in a solid fuel heater comprising a container, a solid fuel therewithin with a wicking means, and a combustible insert sleeve which is fitted inside of the container and extends above the surface of the solid fuel. In a further embodiment, the sleeve includes supporting legs which are useful in positioning the sleeve in the container at the proper height While the fuel is being poured into the container.

The invention includes fabrication of a blank for an insert sleeve to be used in the solid fuel heater, although the insert sleeve can be stamped or otherwise formed from a sheet of combustible material. Then the insert sleeve is formed into a desirable configuration such as a triangle supported on legs.

In fabricating the solid fuel heaters, a scoop of oiled perlite is placed into a container. Next, an insert sleeve is fitted into the container and held in position by friction or by the supporting legs resting on the base of the container, and a molten fuel composition is poured into the container and left to cool and harden.

Brief description of the drawing FIG. 1 is an elevation cross section of a solid fuel heater as manufactured in the prior art;

FIG. 2 is a plan view of a container for a solid fuel heater of the present invention with an insert sleeve embedded therein;

FIG. 3 is an elevation section of the solid fuel heater of FIG. 2, taken along the line 33 thereof;

FIG. 4 is an isometric view of an embodiment of the insert sleeve of the present invention;

FIG. 5 is a blank with scorings thereon for providing a T-section insert sleeve; and

FIG. 541 discloses a blank with scorings thereon for providing an insert sleeve with tapered supporting legs.

Description of the preferred embodiment Reference is made to the figures of the drawing wherein a container 2 which has a bottom 3 and upstanding sidewalls 5, and is shown as substantially filled with a solid fuel 4. In the prior art (FIG. 1), as the molten fuel cooled, it hardened irregularly to enclose a void or vug 6 in the upper central portion below the wicking means 10 for the solid fuel 4.

The contraction of the fuel during cooling also tends to develop a separation or void 8 from the inside wall of the container 2 and is shown exaggeratedly.

Thus, when the heater was ignited, the molten fuel drained away from the combustion area into vugs, voids, or the separation so that the flame, with little or no fuel, burned weakly before going out.

A wicking means 10 such as oiled perlite can be mixed with the solid fuel while molten so that continually new wicking means are always available to the flame. Alternately the wicking means can be allowed to float to the top of the molten fuel in the container 2.

The solid fuel heater can be ignited readily by pouring a small amount of a lighter fluid over the wicking means at the top of the container. As the heater burns, the solid fuel 4 adjacent the flame melts and through the capillary action of the wicking means is fed to the flame.

The solid fuel has the same composition as disclosed in the coassigned patent viz. 90 to 99.9% of a wax component containing from 6.1 to 10% by weight of a buoyant particulate material component in contact with said wax to increase the burning rate of said composition, the buoyant material being selected from the group consisting of expanded vermiculite, shredded cork, perlite, pumice, hollow glass spheres having an average diameter of about 100 microns, perlite-vermiculite, perlite-cork and perlitepumice mixtures.

FIGS. 2, 3 and 4 disclose the novel insert sleeve 12 of the present invention, having a triangular body 13 from which extend supporting means or legs 14, placed upright within the container 2 before filling the container with molten fuel 4. The body 13 should fit snugly into place Within the container, and the legs 14 are to assure that the insert sleeve 12 is positioned at the right height therewithin, as may be predetermined for the particular size of container being used.

This insert sleeve serves two main functions. As the fuel 2001s and solidifies, it does not adhere to the insert sleeve but slips down into the body of the fuel thereby avoiding :he formation of voids or vugs. Also, the insert sleeve, projectin above the top surface of the solid fuel 4, acts as a Well to hold both the initial lighting fluid and later the molten fuel itself, preventing either from running into the void 8 along the inside of the container wall. Even with a small vug in the solid fuel, the flame will receive enough molten fuel to continue burning at the same rate. The insert sleeve also prevents slopping and loss of materials while the fuel is molten. Additionally, the sleeve is important for use with a light wind blowing, because it acts as a flame holder to sustain ignition and burning.

When the sleeve is formed with legs, they may be of any desired configuration, so long as space exists for the flow of molten fuel therebetween. With the insert sleeve embedded at full depth in the solid fuel in the container, it serves as a supplementary wick to the primary wick (oiled perlite).

Particular leg shapes include the rectangular waveform as disclosed in FIG. and the sawtooth waveform of FIG. 5a, these figures disclosing blanks for the insert sleeve which have been scored for easy detachment and folding into the particular configuration desired.

Reference is made to FIG. 5 wherein a blank 3a of insert sleeve 12 has been scored to form triangular insert sleeves for thermal candles. The scoring on the blank defines insert sleeves comprising three T-shaped sections to make a triangular configuration as outlined by the square Wave shape scoring 32 and the vertical scorings at 34, both for separation of individual sieeves.

The blank of insert sleeves may have additional indications for folds, as shown by the dash lines at 36, to form the particular geometric shape of sleeve desired, in this case, a triangular shape. It is evident that the blank could be a roll and the scorings made so that any pluralities of legs could be used for the insert sleeve to define various geometric shapes.

While the vertical separation scorings at 34 are shown as offset from the vertical scorings of the square wave shape, both vertical scorings could be made to coincide.

FIG. 5a discloses a blank 30a with a separation scoring 32a, to define a saw tooth configuration for insert sleeves l2a. Corresponding to the vertical separation scorings In FIG. 5, there are the vertical scorings at 34a and the fold indications or scorings at 36a. The legs 14 of the ;leeve 12 are set on the bottom of the container before nolten fuel is poured therein. The edges of the sleeve are lesigned to fit snugly against the inside of the container to prevent flotation of the insert sleeve when the molten fuel is poured therein. The snug fit also makes it easy to cen- ;er the sleeve within the container.

In a method of fabricating thermal heaters according to an embodiment of the present invention, a scoop of oiled perlite, for use as a wicking means 10 is placed into a container 2. An insert sleeve 12 is then fitted snugly into the container so that it is even with or projects slightly above the top edge of the container. A molten fuel, the composition of which is the same as that disclosed in the above cited, coassigned patent viz. essentially to 99.9% by weight of a wax component containing from 0.1 to 10% by weight of a buoyant particulate material component in contact with said wax to increase the burning rate of said composition, the buoyant material being selected from the group consisting of expanded vermiculite, shredded cork, perlite, pumice, hollow glass spheres having an average diameter of about microns, perlite-vermicuiite, perlite-cork and perlitepumice mixtures is then poured into the container until substantially filled, the filled container being left to cool and harden.

Thus, there has been shown and described, a novel insert sleeve for orchard heaters which insures a better performance by improving the state of the solid fuel and providing a reservoir for molten fuel upon ignition.

It is obvious, of course, that variations may be made in the geometry of the insert sleeve, and the blank from which it is made as well as the method of fabricating the insert sleeve itself and the thermal candle with the insert sleeve embedded therein, without departing from the essential attributes of the invention.

We claim:

1. A meltable solid fuel heater comprising a container having upstanding sidewalls and a bottom, a non-circular combustible sleeve shaped insert having formed corners in contact with said upstandin sidewalls to provide an enclosed centrally positioned area positively spaced from said sidewalls and separate from discrete remaining areas defined by said sidewalls, said corners, and portions of said sleeve between consecutive corners, so that melted fuel in said centrally positioned area is prevented from flowing into contraction voids between said solid fuel and said sidewalls, said centrally positioned area enclosing more than one-third of the total area enclosed by said sidewalls, leg means having spaces therebetween for the flow of molten fuel and supporting said insert upright Within said container, said separate area being recombined with said discrete remaining areas when said solid fuel heater burns to below the bottom of said sleeve providing thereat the full surface of the area within said sidewalls, as a reservoir of melted fuel to support combustion across said entire surface of melt, and a wick formed of particulate material capable of floating on melt of said solid fuel, said insert acting in conjunction with said solid fuel when cooling from a molten state to cause said molten solid fuel to slip down upon itself and compact itself so that voids are not developed in said fuel and said solid fuel in said container burns totally in a controlled manner.

2. A solid fuel heater as defined in claim 1, wherein said sleeve has a triangular cross section.

3. A solid fuel heater as defined in claim 1, wherein said sleeve is formed from sections having generally triangular legs.

4. A solid fuel heater as defined in claim 1, wherein said sleeve formed from T-shaped sections.

5. A solid fuel heater as defined in claim 1, wherein said fuel has the following composition: 90 to 99.9% of a wax component containing from 0.1 to 10% by weight of a buoyant particulate material component in contact with said wax to increase the burning rate of said composition, the buoyant material being selected from the group consisting of expanded vermiculite, shredded cork, perlite, pumpice, hollow glass spheres having an average diameter of about 100 microns, perlite-vermiculite, perlitecork and perlite-pumice mixtures.

6. A method of making a solid fuel heater which comprises the steps of:

(a) forming a combustible sheet material into a sleeve having a plurality of angular corners and substantially flat side portions between said corners;

(b) fitting said sleeve into an open top container having upstanding sidewalls and a bottom;

(c) supporting said sleeve from said bottom and positioning said corners in contact with said sidewalls to define an area within said sleeve and a plurality of areas outside said sleeve and between said sleeve and said sidewalls;

(d) filling said container with wicking means and molten fuel to below the top edges of said sleeve and said container; and

(e) cooling said molten fuel in said container to a solid state while allowing said fuel to slip down and compact itself along said sleeve during said cooling, thereby providing a walled enclosure with said sleeve capable of retaining said molten fuel during ignition of said heater from flowing into a contraction void developed during cooling between said fuel and the wall of said container, so that there is a continuous supply of molten fuel for continuous ignition at said wicking means while said contraction void is filled with molten fuel flowing from said areas outside said sleeve.

7, A method as defined in claim 6 wherein said sleeve is supported on legs and step (b) includes fitting said sleeve into said container so that said legs rest on the bottom of said container.

8. In a method as defined in claim 6 wherein said fuel comprising a heating composition substantially filling said container, said composition consisting essentially of from to 99.9% by weight of a wax component and from 0.1 to 10% by weight of a buoyant particulate material component in contact with the wax component, said buoyant particulate material being present in the container to increase the burning rate of said wax, said buoyant material being selected from the group consisting of expanded vermiculite, shredded cork, perlite, pumice, hollow glass spheres having an average diameter of about microns, perlite-vermiculite, perlite-cork and perlite-pumice mixtures.

References Cited UNITED STATES PATENTS 2,168,698 8/1939 Bunt et al 431291 2,354,343 7/1944 Webber et al 43 l2'89 3,338,691 8/1967 Knowles et al.

3,367,758 2/1968 Ambrose et al. 12659.5 X

CHARLES J. MYHRE, Primary Examiner U.S. Cl. X.R. 12659.5 

